The present invention relates to a polyester support excellent in cutting properties (film cutting and notch forming properties) in a photofinishing laboratory (processing laboratory), excellent in handling properties, and less generation of develop scratches. Further, the present invention relates to a silver halide photographic material using the same.
Silver halide photographic materials (hereinafter also briefly referred to as photographic materials) using polyester supports are described in JP-A-6-035118 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d). However, when these photographic materials were used to prepare brownie or 135 system photographic materials and subject them to a sequence of processing steps in a photofinishing laboratory (processing laboratory), poor cutting occurred in cutters mounted on a miniature laboratory, a splicer and a mounter for reversal. The reason for this is that the polyester supports high in mechanical strength and poor in cutting properties are difficult to be cut, because TAC supports that have previously been used are very easy to be cut and the cutters are adjusted thereto.
For solving this problem, anisotropic stretching (twice or less in a machine direction (MD) and 2.5 to 6 times in a transverse direction (TD)) as described in JP-A-10-293381 is proposed. However, when photographic materials using supports obtained by such anisotropic stretching were allowed to pass through a sequence of processing steps in a processing laboratory, poor cutting occurred in a notch forming step. The term xe2x80x9cnotchxe2x80x9d as used herein means a half-round opening having a diameter of 3 to 8 mm formed for recognizing a position of an image in a printer. In the anisotropic supports prepared in the above-mentioned patent, isotropic half-round openings can not be formed precisely. It has been therefore desired that such disadvantage is overcome.
Further, a method of mixing polyesters different from each other in intrinsic viscosity as described in JP-A-11-202446 is proposed. According to this method, however, not only the load in cutting and notch forming is heavy, but also flashes (remainders remaining at cut portions without being cut away) are generated in large amounts. Such disadvantage has therefore been desired to be overcome. Furthermore, the use of a polyester low in intrinsic viscosity, that is to say, low in molecular weight, is liable to produce scratches during development and printing under a low-moisture atmosphere in a processing laboratory. It has been therefore desired that such problem is solved.
An object of the present invention is to provide a polyester support excellent in cutting properties (film cutting and notch forming properties) in a photofinishing laboratory (processing laboratory), excellent in handling properties, and difficult to generate scratches.
Another object of the present invention is to provide a silver halide photographic material using such a polyester support.
These objects have been attained by a polyester support having both transverse direction (TD) and machine direction (MD) breaking strengths of from 5 kg/mm2 to 18 kg/mm2, and both transverse direction (TD) and machine direction (MD) breaking elongations of from 20% to 140%.
Further, these objects have also been attained by a polyester support having both transverse direction (TD) and machine direction (MD) breaking strengths of from 5 kg/mm2 to 18 kg /mm2, and both TD and MD Young""s moduli of from 400 kg /mm2 to 650 kg /mm2.